\begin{tikzpicture}
    \tkzDefPoints{0/0/A, 2.5/0/B}
    % C 和 D 的角相等
    \tkzDefTriangle[two angles=95 and 25](A,B)  \tkzGetPoint{C}
    \tkzDefTriangle[two angles=40 and 80](A,B)  \tkzGetPoint{D}
    \tkzDefCircle[circum](A,B,C)  \tkzGetPoints{O}{R}

    \tkzDrawPolygon(A,B,C)
    \tkzDrawPolygon(A,B,D)
    \tkzDrawCircle[thick,dashed](O,R)
    \tkzDrawPoint(O)
    \tkzLabelPoints[right](O)
    \tkzLabelPoints[below left](A)
    \tkzLabelPoints[right](B)
    \tkzLabelPoints[above left](C)
    \tkzLabelPoints[above](D)
\end{tikzpicture}

